DURING TAXI FOR TKOF; AN A320'S RT GEN DROPPED OFF LINE AND AFTER 15 SECONDS TRANSFERRED THE LT GEN WITH A LOUD NOISE.

Narrative

ON TAXI OUT FOR TAKEOFF; THE RIGHT GENERATOR DROPPED OFF THE LINE. THE RIGHT AC BUS FAILED TO TRANSFER FOR APPROXIMATELY 15 SECONDS. MULTIPLE ECAMS APPEARED IN RAPID SUCCESSION ALONG WITH THE FIRE WARNING LIGHT AND BELL FOR THE NUMBER 2 ENGINE (THE AIRCRAFT WAS DISPATCHED WITH FIRE WARNING LOOP A ON THE NUMBER 2 ENGINE INOPERATIVE AND THE REMAINING LOOP ACTIVATED WITH THE SUBSEQUENT LOSS OF POWER). THE ECAMS AND THE FIRE WARNINGS DISAPPEARED WHEN THE RIGHT AC BUS TRANSFERRED TO THE LEFT GENERATOR. ONLY THE ECAM FOR THE RIGHT GENERATOR REMAINED. THIS TRANSFER WAS ACCOMPANIED WITH A LOUDER THAN NORMAL RELAY NOISE. WE CONTACTED MAINT AND DECIDED TO RETURN TO THE GATE WITHOUT RESETTING THE RIGHT GENERATOR. WE DID RESTART THE APU AND AS THE APU PICKED UP THE LOAD OF THE RIGHT AC BUS THERE WAS AGAIN A VERY LOUD TRANSFER NOISE. WE RETURNED TO THE GATE AND TURNED THE AIRCRAFT OVER TO MAINTENANCE. THIS AIRCRAFT HAD A PREVIOUS EVENT OF A SIMILAR NATURE WITH THE RIGHT AC BUS THAT DID NOT APPEAR IN THE PRINTABLE AIRCRAFT HISTORY.